We wish to synthesize two type of novel polymers based on proven hypotheses and promising preliminary data. First, we propose the synthesis of multiblock copolymers which have hydrophilic-hydrophobic microdomain surfaces. Secondly, we will synthesis triblock-copolymers containing a hydrophobic block A (commercially available medical polymer), a hydrophilic block B(minimizing protein adsorption and platelet interactions) and a block C consisting of heparin (preventing fibrin formation). It has been shown by preliminary experiments that a multiblock copolymer, polyethylene oxide-polystyrene (PEO-PS) showed suppression of platelet aggregation. Triblock copolymers, PS-PEO-Heparin was biologically active when it was coated on PS surfaces and tested in vitro. The synthesized multiblock copolymers and triblock copolymers will be characterized using TEM, FTIR-ATR and contact angle measurement. Their nonthrombogenicity will be evaluated in vitro assay methods and in vivo using AV shunt rabbits and vascular implants in dogs.